{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/4918"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/4918","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"Beyond the standard model of cosmology : a perturbative approach","abstract":"This thesis concerns higher order perturbations of the standard model of cosmology. The theme is addressed in two distinct research areas. The first area deals with linear perturbations of Bianchi type I model filled with dust whose flow is irrotational, and which is an analogue to second order perturbations about the standard model. We investigate both density perturbations and gravitational waves in the shear dominated and the matter dominated regimes. We find that whereas the analysis of the perturbations in the matter dominated regime recovers the standard FLRW results, the analysis of perturbations in the shear dominated regime reveals that density perturbations and gravitational waves decouple only when the background shear is locally rotational symmetric.","abstract_html":"This thesis concerns higher order perturbations of the standard model of cosmology. The theme is addressed in two distinct research areas. The first area deals with linear perturbations of Bianchi type I model filled with dust whose flow is irrotational, and which is an analogue to second order perturbations about the standard model. We investigate both density perturbations and gravitational waves in the shear dominated and the matter dominated regimes. We find that whereas the analysis of the perturbations in the matter dominated regime recovers the standard FLRW results, the analysis of perturbations in the shear dominated regime reveals that density perturbations and gravitational waves decouple only when the background shear is locally rotational symmetric.","abstract_has_math":false,"creators":["Osano, Bob Otieno"],"institution":"Department of Mathematics and Applied Mathematics","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Dunsby, Peter K S","Clarkson, C A"],"committee_chairs":[],"committee_members":[],"year":2007,"date_issued":"2007","date_published":"2007","updated_at":"2026-07-22T22:23:31Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/4918","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Dunsby, Peter K S","Clarkson, C A"]},{"key":"dc:creator","label":"Author","values":["Osano, Bob Otieno"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-07-31T08:10:19Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-07-31T08:10:19Z"]},{"key":"dc:date.issued","label":"Date","values":["2007"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Mathematics and Applied Mathematics"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/4918"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Includes abstract.","Includes bibliographical references (p. 171-185)."]},{"key":"dc:description.abstract","label":"Abstract","values":["This thesis concerns higher order perturbations of the standard model of cosmology. The theme is addressed in two distinct research areas. The first area deals with linear perturbations of Bianchi type I model filled with dust whose flow is irrotational, and which is an analogue to second order perturbations about the standard model. We investigate both density perturbations and gravitational waves in the shear dominated and the matter dominated regimes. We find that whereas the analysis of the perturbations in the matter dominated regime recovers the standard FLRW results, the analysis of perturbations in the shear dominated regime reveals that density perturbations and gravitational waves decouple only when the background shear is locally rotational symmetric."]},{"key":"dc:title","label":"Title","values":["Beyond the standard model of cosmology : a perturbative approach"]}]}],"canonical_facts":{"dc:contributor.advisor":["Dunsby, Peter K S","Clarkson, C A"],"dc:creator":["Osano, Bob Otieno"],"dc:date.accessioned":["2014-07-31T08:10:19Z"],"dc:date.available":["2014-07-31T08:10:19Z"],"dc:date.issued":["2007"],"dc:description":["Includes abstract.","Includes bibliographical references (p. 171-185)."],"dc:description.abstract":["This thesis concerns higher order perturbations of the standard model of cosmology. The theme is addressed in two distinct research areas. The first area deals with linear perturbations of Bianchi type I model filled with dust whose flow is irrotational, and which is an analogue to second order perturbations about the standard model. We investigate both density perturbations and gravitational waves in the shear dominated and the matter dominated regimes. We find that whereas the analysis of the perturbations in the matter dominated regime recovers the standard FLRW results, the analysis of perturbations in the shear dominated regime reveals that density perturbations and gravitational waves decouple only when the background shear is locally rotational symmetric."],"dc:identifier.uri":["http://hdl.handle.net/11427/4918"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Mathematics and Applied Mathematics"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["Beyond the standard model of cosmology : a perturbative approach"],"dc:type":["Doctoral Thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["PhD"]},"updated_at":"2026-07-22T22:23:31Z"}